This invention relates generally to luminaires and more particularly to latch and hinge mechanisms for fastening refractor and the like panels thereof to the housing of the luminaire.
Various types of mechanisms have been used to fasten refractor and the like panels to a luminaire housing. These mechanisms must provide an adequate seal to minimize the entry of dust and moisture into the housing as well as to be readily and quickly releasable to provide access to the housing interior for maintenance purposes.
A mechanism which meets the last-mentioned requirements and in addition not only performs the function of latching but serves as a hinge so that upon release the refractor panel can be swung away from the luminaire housing at one end thereof but not be completely removed therefrom, if desired, is shown in U.S. Pat. No. 3,943,355.
The latch and hinge mechanism of the last-mentioned U.S. patent comprises four spring loaded plunger rods or pins which are mounted within recesses or channels defined at the four corners of the frame portion of the refractor panel. The plunger rods operate in pairs such that a first pair is on a common axis along one edge of the frame while the other pair is on a second common axis on the opposite edge of the frame The rods or pins are biased outwardly from the corners of the frame and are manually retractable into the frame. Upon placing the frame into a complementarily shaped opening at one end of the luminaire housing, the rods are released and enter aligned apertures provided in the side walls of the luminaire housing to hold the refractor panel thereto. If desired, either pair of the rods can be released so that a corresponding end of the refractor panel may be swung away from the housing and about the opposite pair of rods. Also, if desired, all four plunger rods may be released for removal of the refractor panel from the luminaire housing.
In the case of the above-described latch and hinge mechanism, tabs or the like portions of the plunger rod which can be manually manipulated to move the plunger rods into a retracted position in the frame, are all located on the outside or exposed surface of the refractor panel and as such are all accessible when the panel is mounted on the luminaire housing. Accordingly, one is able to release both pairs of plunger rods from the outside of the luminaire. In such case, it is also possible that one repairing a luminaire of the type described may inadvertently release two plunger rods which are not of the same pair. If this should occur, it is quite likely that the refractor panel would fall from the luminaire housing and could thereby become damaged. Furthermore, if the luminaire were located in an elevated position, on a post or at the side of a building, for example, the improper release of the refractor panel could cause injury to persons below or to the person making the repairs.
In addition to the above, it appears from the description of the latch and hinge assembly of the U.S. Pat. No. 3,943,355 that the refractor panel is designed for mounting on a luminaire housing in one position only, thereby permitting the refractor panel to be swung away from the housing only at either of two opposite ends thereof. In some cases where the luminaire is positioned so that it would be more easily accessible for repair if the refractor panel could be swung away at a side of the luminaire housing other than such two opposite ends, the arrangement of the U.S. Pat. No. 3,943,355 would not be suitable.